JPS6139750Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a cylinder device suitable for a boom such as a hydraulic crane.

For safety reasons, it is desirable for the crane boom to extend sequentially from the proximal end to the distal end when extended, and to contract sequentially from the distal end to the proximal end when retracted. The applicant previously filed Japanese Patent Application No. 53-117980 (Japanese Unexamined Patent Publication No. 55951-1982) and Japanese Patent Application No. 31461-1987 regarding the technical concept of two cylinder devices in which each cylinder device sequentially expands and contracts. These applications attempted to achieve sequential expansion and contraction using a pilot operation method, resulting in complicated structures. In the present application, the structure is simplified by sequentially expanding and contracting using a linear motion system.

The present invention will be explained below with reference to the drawings.

FIG. 1 shows an example of the present invention, in which A is a first cylinder consisting of a cylinder part a ¹ and a piston rod part a ² .
Cylinder device B is a second cylinder device consisting of a cylinder part b ¹ and a piston rod part b ² , and is normally attached to a three-stage boom at the arrangement position shown in the figure. That is, the piston rod part ^a2 of the first cylinder device A is connected to the base end boom 101, and the cylinder part ^a1 and the second cylinder device B are connected to the base end boom 101.
A three-stage telescopic boom is constructed by attaching the cylinder part b ¹ to the intermediate boom 102 and the piston rod part b ² to the tip boom 103 (see FIG. 7). 1 is an oil tank, 2 is an oil pump, and 3 is a control valve, which constitute an oil supply and discharge device. 4 is a pipe connected from the control valve 3 to the extension side oil chamber 16 of the first cylinder device A, 5 is a pipe connected to the contraction side oil chamber 10, and 6 is a piston rod connected to the contraction side oil chamber 10 of the first cylinder device.
Port provided at the end of a ² , 8 is the same extension side oil chamber 1
6, a port 7 connects the reduction side oil chambers 10 and 14 of the first cylinder device A and the second cylinder device B, and 9 connects the reduction side oil chamber 10 of the first cylinder device A with the aforementioned one. Piston rod connecting to port 6
This is a passage within a ² and communicates with the reduction side oil chamber 10 via an oil passage 56 . 10 is a contraction side oil chamber of the first cylinder device A, 11 is a port of the contraction side oil chamber 14 of the second cylinder device B, and 12 is provided in the piston rod ^a2 of the first cylinder device A, and the piston 15 is connected to the piston 15. A middle pipe that penetrates and reaches the cylinder end portion 52,
A first valve 24 is provided at the cylinder end portion 52. Also, the middle pipe 12 is normally pushed to the left by the spring 21, and the first valve 24 blocks off the oil chamber 22 and the oil chamber 34, but at the end of the extension of the first cylinder A, the end 54 of the middle pipe 12 in contact with the piston 15,
It is moved to the right, and the first valve 24 is operated so that the oil chamber 22 and the oil chamber 34 are communicated with each other. 13 is a passage of the middle pipe 12, one side of which communicates with the aforementioned port 8, and the other side of which communicates with the oil chamber 57 within the first valve 24. 23 is this oil chamber 57 and the aforementioned oil chamber 22
A passage 33 connecting the oil chamber 34 is a check valve provided in the oil chamber 57 and is always urged by a spring 48, allowing oil to flow from the oil chamber 34 to the oil chamber 57 side, but preventing its reverse flow. The oil chamber 34 has a passage 58 and a port 5.
3. The piping 32 communicates with the extension side oil chamber 20 of the second cylinder device B via a port 55 provided in the cylinder end portion 19 of the second cylinder device B.
18 is a piston of the second cylinder device B. Next, 38 is a second valve provided in the cylinder end portion 52 of the first cylinder device A, which is always urged by a spring 35 to close the oil chamber 59 and the oil chamber 60. When activated, it has a check effect that allows oil to flow from oil chamber 59 to oil chamber 60, but prevents the reverse flow. Note that the second valve 38 is in an unrestricted state and one end 38a thereof is connected to the cylinder end portion 52.
On the other hand, an engager 65 is provided at the tip of the piston rod ^b2 of the second cylinder device B, and at the end of the contraction of the second cylinder device B, this engager 65 is connected to the end of the piston rod b2. engaged with the second
By pushing the valve 38 against the spring 35, the oil chamber 59 and the oil chamber 60 are configured to communicate with each other.
61 is a passage connecting the oil chamber 59 and the aforementioned oil chamber 22, and 62 is a passage connecting the oil chamber 60 and the extension side oil chamber 16 of the first cylinder device A. In addition, 51 is the ground part of the first cylinder device A, 64 is the port of the contraction side oil chamber 10 of the first cylinder device A to which the piping 7 is connected, and 63 is the port of the supply/discharge port 6, 8 of the first cylinder device A. A counterbalance valve installed near the inlet allows pressure oil to flow from the piping 4 side to the port 8 side when extended, and prevents pressure oil from flowing in the opposite direction; It is configured to be actuated by pilot pressure from the side to allow flow in the opposite direction.

Next, the operation of the cylinder expansion and contraction device provided with the sequential operation mechanism configured as described above will be explained.

In FIG. 1, both the first and second cylinder devices A and B are in the most contracted state. In this state, when the control valve 3 is pushed to the left and switched to the position shown in FIG.
3. The oil enters the oil chamber 22 via the oil chamber 57 in the first valve 24 and the passage 23. Since the first valve 24 is pushed to the left by the spring 21, the oil chamber 22 and the oil chamber 34 are not in communication with each other, so that the pressure oil does not flow into the second valve.
It does not go to the extension side oil chamber 20 of the cylinder device B, and the second cylinder device B does not extend. The pressure oil in the oil chamber 22 reaches the oil chamber 59 via the passage 61, and the oil chamber 6
0, it flows into the expansion side oil chamber 16 of the first cylinder device A across the passage 62, and the first cylinder device A expands. In this case, suppose that the second cylinder device B is slightly extended, and therefore the end 38a of the second valve 38 is not pressed by the engagement element 65, and the spring 35 causes the oil chamber 59 and the oil chamber 60 to be connected. In the case where it is closed, the second valve 38 is opened by the pressure oil acting on the oil chamber 59, and the pressure oil flows into the extension side oil chamber 16 of the first cylinder device A, and the first cylinder device is extended. When the first cylinder device A expands in this manner, the oil in the contraction side oil chamber 10 of the first cylinder device A returns to the tank 1 via the passage 56, passage 9, port 6, and piping 5. The state shown in Figure 2 progresses,
When the first cylinder device A reaches its maximum extension, the end portion 54 of the middle pipe 12 and the piston 15 of the first cylinder A come into contact with each other. At this point, the first valve 24 is still pushed to the left by the spring 21, so the circuit is similar to the state shown in FIG. 2, but pressure oil also enters the extension side oil chamber 16 of the first cylinder device A. The force of the spring 21 is defeated by the thrust generated on the piston 15 by the pressure oil in the oil chamber 16, and the first valve 24 is moved to the right, and the oil chamber 22 and the oil chamber 34 are communicated with each other, resulting in the state shown in FIG. 3. becomes. As shown in FIG. 3, the oil chamber 22 and the oil chamber 34 communicate with each other.
The pressure oil enters the extension side oil chamber 20 of the second cylinder device B via the passage 58 and the piping 32. This results in
The second cylinder B begins to expand. On the other hand, from the oil chamber 22, the passage 61 passes through the oil chamber 59, the oil chamber 60, and the passage 62.
As the piston 15 comes into contact with the gland 51 of the first cylinder A and the extension of the first cylinder device stops, the pressure oil that was communicating with the extension side oil chamber 16 of the first cylinder device A no longer flows. No inflow.

FIG. 4 shows a state in which the first cylinder device A stops extending and the second cylinder device B continues to extend.
When the second cylinder device B is extended, the end portion 38a of the second valve 38 is brought into a non-contact state with the engagement element 65, and the second cylinder device B is expanded.
The valve 38 shuts off the oil chamber 59 and the oil chamber 60, which are pushed to the left by the force of the spring 35. Note that even if the oil chamber 59 and the oil chamber 60 are in the cutoff state, if the first cylinder device A is in the expandable state (assuming that the first cylinder device A is contracted for some reason), the pressure oil is in the first cylinder device A. The second valve 38 is pushed open and the oil flows into the extension side oil chamber 16, and the first cylinder device A is extended. This means that during extension, the first cylinder device A is always held in the most extended state. With the expansion of the second cylinder device B, the oil in the contraction side oil chamber 14 is
It passes through the port 11, the piping 7, the contraction side oil chamber 10 of the first cylinder device A, the passage 9, and the port 6 and returns to the tank.

Next, the reduction operation will be explained.

When the control valve 3 is switched as shown in FIG.
However, the oil in the extension side oil chamber 16 of the first cylinder device A is transferred to the oil chamber 59 and the oil chamber 60 by the second valve 38.
cannot escape because it is blocked by the first
Cylinder device A does not contract. The oil in the extension side oil chamber 20 of the second cylinder device B is connected to the port 55 and the piping 3.
2. The oil chamber 34 is reached through the passage 58, and the oil chamber 22
The oil flows into the oil chamber 57 in the valve 24 via the check valve 33 or by directly pushing open the check valve 33, and then returns to the tank 1 via the passage 13 and the port 8. The second cylinder device B is therefore reduced.

If the first cylinder device A does not contract and only the second cylinder device B contracts, the second cylinder device B
The engaging element 65 provided at the tip of the piston rod ^b2
contacts the end 38a of the second valve 38, overcomes the force of the spring 35 pushing the second valve 38, and the oil chamber 59 and the oil chamber 60 communicate with each other, resulting in the state shown in FIG. 6.

When the oil chamber 59 and the oil chamber 60 communicate with each other as shown in FIG.
1, the oil chamber 22, the oil chamber 57 in the first valve 24, and further returns to the tank via the passage 13, port 8, etc. When the first cylinder device A starts to contract, the piston 15 moves to the left, and the piston 15 and the end 54 of the middle pipe 12 are in a non-contact state, so that the first valve 24 is returned to the left by the spring 21. , the oil chamber 34 and the oil chamber 22 are shut off. At this time, even if pressure oil accumulates in the oil chamber 34 etc., or even if the second cylinder device B is not completely retracted, the extension side oil chamber of the second cylinder device B The oil No. 20 pushes open the check valve 33 and escapes to the tank side. This means that during contraction, the second cylinder device B is always held in the minimum contraction state.

As the oil in the extension side oil chamber 6 of the first cylinder device A returns to the tank 1 in this manner, the first cylinder device A becomes the most contracted state shown in FIG.

Next, other embodiments of the present invention will be described.

FIG. 8 shows another modification of the first valve 24 described above. That is, the first valve 24 is in the illustrated position (FIG. 8) to block the flow of oil from the oil chamber 22 to the oil chamber 34, and the first valve 24 prevents oil from flowing from the oil chamber 34 to the oil chamber 22 by the pressure oil in the oil chamber 34. It suffices if it has a so-called check function, which allows the flow to flow by pushing and opening the valve 24. In the above-mentioned system, the check valve 33 is especially provided to check the oil chamber 3.
4 to the oil chamber 57 (on the oil chamber 22 side), this is to reduce the pressure loss of the oil flow in this direction, and in principle, the first valve 2
4 itself may have a check function. The valve 24 shown in FIG. 8 represents this embodiment. In this case, the pressure to push the first valve 24 open by itself using the pressure oil in the oil chamber 34 must be strong enough to overcome the spring 21 biasing the first valve 24 to close, so it will be slightly higher.

Next, FIG. 9 shows an embodiment in which a counterbalance valve 66 is provided in the supply/discharge circuit (piping 32) to the extension side oil chamber 20 of the second cylinder device B.
This prevents oil from flowing backward from the extension-side oil chamber 20 of the second cylinder device B to the extension-side oil chamber 16 of the first cylinder device A. The cylinder expansion/contraction device of the present invention always begins to extend from the first cylinder device, and when the first cylinder device A is fully extended, the second cylinder device B extends, and when retracting, it always starts from the second cylinder device B. The second cylinder device B starts to contract.
This is a configuration in which the first cylinder device A is contracted when the cylinder is in the most contracted state. Therefore, it is theoretically impossible for the first and second cylinder devices to be in a semi-extended state, for example, the state shown in FIG. 10. However, if for some reason (such as an oil leak) the cylinder becomes as shown in Fig. 10 and a load is suspended in this state, the extension side oil chambers of the first and second cylinder devices A and B 16 and 20, and if the pressure in the extension side oil chamber 20 of the second cylinder device B becomes higher than the pressure in the extension side oil chamber 16 of the first cylinder device A (this state Extension side oil chamber 2 of B
(occurs when the pressure receiving area of 0 is smaller than the pressure receiving area of the extension side oil chamber 16 of the first cylinder device A), the second
The pressure oil in the extension-side oil chamber 20 of the cylinder device B opens the port 55, piping 32, port 53, oil chamber 34, and check valve 33 to communicate with the oil chamber 22, oil chamber 59, and oil chamber 60, and then enters the first cylinder. In some cases, the oil may flow into the extension side oil chamber 16 of device A, and in this case, the second cylinder device B will contract and the first cylinder device A will extend, and the boom as a whole will retract by the offset of the expansion and contraction ( Since the pressure receiving diameter of the second cylinder B is smaller than that of the first cylinder device A, the contraction of the second cylinder device B is larger than the expansion of the first cylinder device A).

Note that in the opposite case (when the pressure in the extension side oil chamber 16 of the first cylinder device A increases), the oil flows through the second valve 3.
8 and does not pass to the second cylinder device B. The counterbalance valve 66 is provided to solve this problem. Note that even in the state shown in FIG. 10, if the control valve 3 is switched, the first cylinder device A will always extend when it is extended.
When retracting, the second cylinder device B is always retracted.

In addition, FIG. 11 is intended to detect the end of the contraction of the second cylinder device B by the contraction of the tip boom 103.

[Brief explanation of the drawing]

Fig. 1 is a sectional view of the cylinder telescoping device according to the present invention, Figs. 2 to 6 are explanatory diagrams of the operation of the cylinder telescoping device shown in Fig. 1, and Fig. 7 is a cross-sectional view of the cylinder telescoping device according to the present invention. Figure attached to the boom, No. 8
9 and 11 are explanatory diagrams of other embodiments of the present invention, and FIG. 10 is a diagram for explaining FIG. 9. A...First cylinder device, B...Second cylinder device, 10, 14...Reduction side oil chamber, 16, 20...
...Extension side oil chamber, 24...First valve, 38...Second
valve.

Claims (1)

[Scope of utility model registration request] Reduction side oil chamber 1 of first and second cylinder devices A and B
0 and 14, and connects the contraction side oil chamber 10 of the first cylinder device A to an oil supply and discharge device, and connects the extension side oil chamber 16 of the first and second cylinder devices A and B from this oil supply and discharge device. , 20, there is a first valve 24 that operates at the end of extension of the first cylinder device A when it is extended and communicates the oil supply side to the extension side oil chamber 20 of the second cylinder device B when it is retracted. a second valve 38 that operates at the end of the contraction of the second cylinder device B and connects the extension side oil chamber 16 of the first cylinder device A to the oil drain side;
The first valve 24 always communicates the extension side oil chamber 20 of the second cylinder device B to the oil drain side when contracted, and the second valve 38 has one end 38a connected to the first cylinder device A.
This end portion 38a is configured to detect the end of contraction of the second cylinder device B, and directs the extension side oil chamber 16 of the first cylinder device A to the oil drain side. and the oil supply side is always connected to the extension side oil chamber 16 of the first cylinder device A during extension, and furthermore, the oil supply and discharge device is connected to the supply and discharge ports 6 and 8 of the first cylinder device A.
In the middle of the piping to the extension side, the flow of oil to the oil chamber on the extension side is allowed and the flow in the opposite direction is blocked, but it is activated by the pilot pressure from the oil supply side when the oil is contracted, and the flow in the opposite direction is prevented. A cylinder expansion/contraction device characterized by being provided with a counterbalance valve 63 that allows flow.